Fuel needed for grilling a sausage? (3)
I believe the answer is:
gas
'fuel' is the definition.
(gas is a fuel)
'needed for grilling a sausage?' is the wordplay.
'needed for' says the answer is hidden in the clue (the answer is needed to spell part of the clue).
'GAS' can be found hidden inside 'grilling a sausage'.
(Other definitions for gas that I've seen before include "Nitrogen, say" , "State of matter not solid or liquid" , "eg CO2" , "that may quickly be stepped on" , "Oxygen is one" .)